Method of spin forging a vehicle wheel

Abstract

A method of forming a one piece vehicle wheel is disclosed which method includes the steps of initially forging a rough vehicle wheel shape which is then subjected to a series of spinning operations to contour the rim portion thereof. Part of the final contouring of the rim portion of the wheel is performed without mandrel backing and the entire final contouring is performed after a solution heat treatment thereof in order to assure accurate formation thereof. Additionally, if desired, final machining and/or trimming operations may be performed without removing the wheel from the final contouring apparatus.

I claim: 
     
       1. A method of forming a vehicle wheel out of a spin forging formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions therefrom, a generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and a wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the juncture of said legs;   (b) mounting said forged billet over a chuck having an external contoured surface conforming to the final inside shape of the wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center;   (c) securing said forging on said chuck;   (d) rotating said chuck and forging about the center axis of said wheel;   (e) thereafter forcing the outer periphey of a roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said wheel center; and   (f) thereafter finish forming and sizing both said axial flanges and said drop center.   
     
     
       2. The method of claim 1 wherein said forging is subjected to a solution heat treatment prior to mounting said forging on said chuck. 
     
     
       3. The method of claim 1 wherein said forging includes a roughly formed center opening and said method further comprising advancing cutting means to finish machine the periphery of said center opening while said forging is being rotated with said chuck. 
     
     
       4. The method of claim 3 further comprising the step of advancing said cutting means into engagement with the axially inwardly facing surface of said wheel center surrounding said center opening to face said axially inwardly facing surface of said wheel center. 
     
     
       5. The method of claim 1 wherein said method further comprises forcing the outer periphery of a second roller against said rim in a direction generally radially inwardly and then generally axially away from said wheel center to finish form and size said drop center and axial flange farthest from said wheel center, said second roller outer periphery having a radius of curvature less than that of said first roller. 
     
     
       6. The method of claim 5 wherein said roller and said second roller are moved simultaneously axially away from said radial leg, said second roller trailing slightly behind said roller. 
     
     
       7. The method of claim 5 wherein said forging is secured to said chuck by clamping said forging against a tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire bead retaining flange most adjacent thereto. 
     
     
       8. The method of claim 7 wherein said roller and said second roller are moved radially and axially outwardly from said juncture to finish form said tire bead retaining flange most adjacent said wheel center. 
     
     
       9. A method of forming a vehicle wheel out of a spin formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions therefrom, a generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and a wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the juncture of said legs;   (b) roughly forming and contouring said axial leg;   (c) mounting said roughly formed forged billet over a chuck having an external contoured surface conforming to the final inside shape of the wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center;   (d) clamping said forging against said chuck using a tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire-bead retaining flange most adjacent thereto;   (e) rotating said chuck, forging and tailstock about the center axis of said wheel;   (f) thereafter forcing the outer periphery of a roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said wheel center; and   (g) thereafter finish forming and sizing both said axial flanges and said drop center.   
     
     
       10. A method of forming a one-piece vehicle wheel out of a spin formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions therefrom, an integral generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and an integral wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the juncture of said legs;   (b) mounting the forging from step (a) over a chuck having an external first contoured surface which is in adjacent radial alignment with said axial leg and has an axial dimension substantially greater than that of said axial leg;   (c) rotating said forging and chuck about the center axis of said wheel;   (d) forcing the outer periphery of a first roller generally radially inwardly into the outside surface of said forging at said juncture to reduce the thickness of said axial leg, said outer periphery of said first roller having a given radius of curvature;   (e) thereafter forcing said first roller in a generally axial direction away from said radial leg to axially extend said axial leg along and against said first contoured surface;   (f) forcing the outer periphery of a second roller generally radially inwardly into the outside surface of said forging at said juncture and then generally axially away from said radial leg, said second roller being moved radially during the generally axial movement to roughly contour said axial leg, said outer periphery of said second roller having a radius of curvature less than that of said first roller;   (g) thereafter mounting said forging over a second chuck and clamping said forging against said second chuck using a tailstock, said chuck having a second external contoured surface conforming to the final shape of the inner surface of the rim portion of said wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said second contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center, said tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire-bead retaining flange most adjacent thereto;   (h) rotating said forging and chuck about the center axis of said wheel;   (i) thereafter forcing the outer periphery of a third roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said tire-bead retaining flange most adjacent said wheel center, said third roller outer periphery having a given radius of curvature;   (j) thereafter moving said third roller in a generally axial direction away from said wheel center to roughly form the remainder of said drop center and said axial flange disposed farthest from said wheel center; and   (k) thereafter forcing the outer periphery of a fourth roller against said rim in a direction generally radially inwardly and then generally axially away from said wheel center to finish form and size said drop center and axial flange farthest from said wheel center, said fourth roller outer periphery having a radius of curvature less than that of said third roller.   
     
     
       11. The method set forth in claim 10 wherein said first and second rollers are moved simultaneously axially away from said radial leg. 
     
     
       12. The method set forth in claim 10 wherein said third and fourth rollers are moved simultaneously axially away from said radial leg. 
     
     
       13. The method set forth in claim 10 wherein said third and fourth rollers are also moved in a direction radially outwardly and axially outwardly from said juncture to finish form said tire-bead retaining flange most adjacent said wheel center. 
     
     
       14. The method set forth in claim 13 wherein said finish forming of said bead retaining flange is performed prior to forming steps set forth in h through j. 
     
     
       15. A method of forming a one-piece vehicle wheel out of a spin formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions therefrom, an integral generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and an integral wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the junction of said legs;   (b) roughly forming and contouring said axial leg;   (c) thereafter subjecting said roughly formed forged billet to a solution heat treatment and liquid quenching said roughly formed forged billet to impart a T4 material condition thereto;   (d) thereafter mounting said forging over a chuck and clamping said forging against said chuck using a tailstock, said chuck having an external contoured surface conforming to the final shape of the inner surface of the rim portion of said wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center, said tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire-bead retaining flange most adjacent thereto;   (e) rotating said forging and chuck about the center axis of said wheel;   (f) thereafter forcing the outer periphery of a first roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said tire-bead retaining flange most adjacent said wheel center, said first roller outer periphery having a given radius of curvature;   (g) thereafter moving said first roller in a generally axial direction away from said wheel center to roughly form the remainder of said drop center and said axial flange disposed farthest from said wheel center; and   (h) thereafter forcing the outer periphery of a second roller against said rim in a direction generally radially inwardly and then generally axially away from said wheel center to finish form and size said drop center and axial flange farthest from said wheel center, said second roller outer periphery having a radius of curvature less than that of said first roller.   
     
     
       16. A method of forming a one-piece vehicle wheel out of a spin formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions thereform, an integral generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and an integral wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the juncture of said legs;   (b) mounting the forging from step (a) over a chuck having an external first contoured surface which is in adjacent radial alignment with said axial leg and has an axial dimension substantially greater than that of said axial leg;   (c) rotating said forging and chuck about the center axis of said wheel;   (d) forcing the outer periphery of a first roller generally radially inwardly into the outside surface of said forging at said juncture to reduce the thickness of said axial leg, said outer periphery of said first roller having a given radius of curvature;   (e) thereafter forcing said first roller in a generally axial direction away from said radial leg to axially extend said axial leg along and against said first contoured surface;   (f) forcing the outer periphery of a second roller generally radially inwardly into the outside surface of said forging at said juncture and then generally axially away from said radial leg, said second roller being moved radially during said generally axial movement to roughly contour said axial leg, said outer periphery of said second roller having a radius of curvature less than that of said first roller;   (g) thereafter subjecting said forging to a solution heat treatment to impart a T4 material condition thereto;   (h) thereafter mounting said forging over a second chuck and clamping said forging against said second chuck using a tailstock, said chuck having a second external contoured surface conforming to the final shape of the inner surface of the rim portion of said wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said second contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center, said tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire-bead retaining flange most adjacent thereto;   (i) rotating said forging and chuck about the center axis of said wheel;   (j) thereafter forcing the outer periphery of a third roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said tire-bead retaining flange most adjacent said wheel center, said third roller outer periphery having a given radius of curvature;   (k) thereafter moving said third roller in a generally axial direction away from said wheel center to roughly form the remainder of said drop center and said axial flange disposed farthest from said wheel center;   (l) thereafter forcing the outer periphery of a fourth roller against said rim in a direction generally radially inwardly and then generally axially away from said wheel center to finish form and size said drop center and axial flange farthest from said wheel center, said fourth roller outer periphery having a radius of curvature less than that of said third roller;   (m) thereafter advancing cutting means into engagement with the periphery of said center opening to finish machine said opening and into engagement with an axially inwardly facing surface of said wheel center to finish machine said surface while said forging and said chuck are being rotated.   
     
     
       17. A method of forming a one-piece vehicle wheel out of a spin formable material, wherein said wheel includes a rim having in cross-section a drop center, generally axial integral flanges extending in opposite directions therefrom, an integral generally radial tire-bead retaining flange extending from the outside of each of said axial flanges, and an integral wheel center joining said rim adjacent the axially outer portion of said rim, said method comprising the steps of: (a) forging a billet of said material into the rough shape of the finished wheel, including said wheel center and a rim portion having in cross-section a relatively long axial leg and a relatively short radial leg, said wheel center joining said rim portion in the vicinity of the juncture of said legs;   (b) mounting said roughly formed forged billet on a chuck and rotating said chuck;   (c) roughly forming said axial leg by means of spinning rollers;   (d) thereafter mounting said forging on a second chuck and clamping said forging against said second chuck using a tailstock, said chuck having an external contoured surface conforming to the final shape of the inner surface of the rim portion of said wheel from the minimum inside diameter portion of said drop center to the axially outer surface of the tire-bead flange disposed furthest from said wheel center, said contoured surface extending generally axially in the opposite direction from the minimum diameter portion of said drop center to the inside axial surface of said wheel center, said tailstock having a contoured surface conforming to the radially outer outside surface of said wheel center and said tire-bead retaining flange most adjacent thereto;   (e) rotating said forging and chuck about the center axis of said wheel;   (f) thereafter forcing the outer periphery of a first roller against said axial leg of said rim in a direction generally radially inwardly and axially toward said wheel center to roughly form the side of said drop center nearest said wheel center, the force and direction being controlled to prevent collapsing or distortion of an unsupported portion of said axial flange disposed between said drop center and said tire-bead retaining flange most adjacent said wheel center, said first roller outer periphery having a given radius of curvature;   (e) thereafter forcing the outer periphery of a second roller against said rim in a direction generally radially inwardly adjacent said juncture and advancing said second roller axially toward the roughly formed side of said drop center to finish form said axial flange most adjacent said wheel center;   (h) thereafter moving said first and second rollers in a generally axial direction away from said wheel center together, said second roller being circumferentially spaced and slightly axially trailing said first roller, said first roller roughly forming the remainder of said drop center and said axial flange disposed furthest from said wheel center and said second roller finish forming and sizing said drop center and said axial flange furthest from said wheel center.   
     
     
       18. The method set forth in claim 15 wherein said second roller is moved generally axially toward said first roller after said first roller roughly forms said side of said drop center nearest said wheel center and prior to general axial movement thereof.